On Septemat the 67th United Nations General Assembly at the U.N. In Israel, the phrase was notably used as a political metaphor by Foreign Minister Yigal Allon, in 1975, when said that Washington 'has managed to draw a red line which all the Arab countries know they must not cross - that America is not going to sacrifice Israel for the sake of Arab support.' Yitzhak Rabin later used the phrase to refer to the line past which the Syrian Army should not be allowed to cross after the 1976 occupation of Lebanon. Uniquely, in France one would 'cross the yellow line' ( franchir la ligne jaune). The expression remained significant to global diplomacy and was reused during the UN's founding after the WWII, especially in the English-speaking world.

At the time of signature, the borders of the former empire were not clear and to remedy the problem an Armenian businessman named Calouste Gulbenkian, took a red pencil to draw in an arbitrary manner the borders of the divided empire. The origin of the phrase in English traces back to the ' Red Line Agreement' in 1928 between largest oil companies of Britain, the USA and France at the time of the end of the Ottoman Empire. The Red line, or 'to cross the red line', is a phrase used worldwide to mean a figurative point of no return or line in the sand, or 'the fastest, farthest, or highest point or degree considered safe.' Origins For other uses, see Red Line (disambiguation).

Redline steel assault flag